Support for GNAP Authorization

[rolsonquadras]

Need to implement GNAP authorization for communication between TrustBloc components. Currently, it's a mix of zcap and oauth based on individual APIs. The goal is to have a common auth framework for all components and APIs.

The initial design can be found here.

The hub-auth project will work as an Authorization Server. This needs to implement following main APIs.

• grant request endpoint
• introspect

Also, it needs to provide reusable client sdk to generate grant requests and add httpsign for all the requests sent during the flows along with verification of signatures.

High level tasks:

• Authorization Server:
  • GNAP Auth server session manager #183
  • GNAP Auth server access policy #184
  • REST Endpoints
    • [gnap] Request access (tx) API #164
    • Continue API
    • [gnap] Introspect API #165
  • http signature validator for GNAP resource server API and auth server  #185
  • GNAP auth server nonces and validation #203
  • [gnap] support additional key types for httpsig #221
  • [gnap] update http-signature support to latest version of http-signature spec #223
• Authorization Server - [gnap] Redirect-Based User Interaction #166
• GNAP Client - [gnap] create client/sdk #160
  • Generate GNAP access request - [gnap] Generate access request #161
  • Validate GNAP token - [gnap] Validate token #162
    • http signature validator for GNAP resource server API and auth server  #185
• [gnap] bdd tests #167
  • call request access endpoint
  • sign-in with demo oidc provider
  • return GNAP access token
  • validate GNAP access token through introspect
• Wallet Integration